Oximeter with marking feature

ABSTRACT

A medical device such as an oximeter includes a marking feature. In an implementation, a marking mechanism of the device marks tissue based on a location of where a measurement was taken by the device. In an implementation, the marking mechanism of the device marks tissue based on an oxygen saturation measurement obtained by the device.

BACKGROUND OF THE INVENTION

The present invention relates to the field of medical devices, and morespecifically to an oximeter or other medical device having a markingfeature.

Medical devices are among the marvels of modern medicine. Doctors andpeople use instruments to help diagnose and treat medical conditions andassist in medical and other procedures. Some revolutionary medicaldevices include the balloon catheter, oximeter, stent, and shunt. Overthe years, these have improved the lives of many millions ofpeople—allowing them to live better, longer, and more fulfilling lives.

Medical devices continue to evolve and improve. Today's medical devicesare more accurate, effective, and easier to use than those introducedjust a few years ago. Many types of medical devices are even sold forpeople to use at home. Some common medical devices used by people athome are for monitoring blood pressure, blood glucose, fertility, bodytemperature (instantly and accurately), and body fat percentage.

Despite the widespread success of current medical devices, there is aneed for new and improved medical devices that provide greater featuresand functionality, and devices which generally help improve the lives ofhuman beings.

Oximeters are medical devices used to measure oxygen saturation oftissue in patients. Typically, an oximeter takes a measurement at asingle location. For some medical procedures, it is important to obtainoxygen saturation readings at numerous positions or points across anarea of tissue.

A doctor can use an oximeter to spot check multiple locations. Forexample, to make two successive measurements, the doctor will place asensor at a first location and make a first measurement, and then movethe sensor to a second location to make a second measurement. Any numberof measurements may be made using this spot-checking approach across atissue surface.

Using such an approach, the doctor will have to take and remember thereadings at multiple positions across the tissue region. The number ofreadings may be large. The process of remembering where measurementswere taken and what the measurements were at those points may becomeinefficient and burdensome during any procedure, especially when apatient is in critical condition.

For example, when transplanting tissue, a doctor needs oxygen saturationmeasurements at multiple points of the tissue to ensure blood flow(carrying fresh oxygen) is uniform throughout the tissue region. Thedoctor will have to remember the readings taken at multiple positionsacross the tissue region. Based on these readings, the doctor will makeadjustments as needed (e.g., alter how blood vessels are connected).Otherwise, portions of the tissue not receiving sufficient oxygen flowwill eventually die.

Therefore, an oximeter with a marking feature is needed. It is desirablethat an oximeter indicate where measurements have been made and whatoxygen saturation measurements are at different positions of a tissuearea.

BRIEF SUMMARY OF THE INVENTION

A medical device such as an oximeter includes a marking feature. In animplementation, a marking mechanism of the device marks tissue based ona location of where a measurement was made by the device. In animplementation, the marking mechanism of the device marks tissue basedon a measurement obtained by the device.

By using an oximeter with a marking feature, a doctor can mark a tissuesurface in such a way that the mark reveals the oxygen saturation levelat that point. Thus, the device will mark multiple points of the sametissue immediately after taking each oxygen saturation measurement andbuild a visual map of the tissue's viability. The doctor can then moreeasily reference the points of the tissue at which oxygen saturationmeasurements were taken and compare them in order to make a moreaccurate decision regarding the patient's treatment.

An oximeter with a marking feature gives doctors greater access toinformation relating to a patient's tissue health. For example, tissueviability is an important concern during surgery. By using a tissueoximeter with a marking feature, a doctor can immediately view localoxygen and blood circulation during the procedure.

A marking feature enhances the efficacy of tissue oximeters as itenables doctors and other medical professionals to indicate the specificlocation where a measurement was taken. Furthermore, medicalprofessionals can increase efficiency within the health care field byallowing the oxygen saturation of various points throughout a particulartissue to be immediately visible. A doctor can see the oxygen saturationof a particular tissue just by looking at the markings on the tissuesurface instead of repeatedly taking measurements.

In an implementation, a probe for a medical device includes: a cableinterface, the cable interface being adapted to allow the probe to beconnected to a first radiation emitter and a first photodetector, wherethe first radiation emitter and the first photodetector are external tothe probe. There is a sensor unit including a first source structure anda first detector structure. The first source structure is arranged to beconnected to the first radiation emitter via the cable interface. Thefirst detector structure is arranged to be connected to the firstphotodetector via the cable interface. There is a marking mechanismoutput which positioned closer to the first detector structure than thecable interface.

In a specific implementation, the sensor unit includes a second sourcestructure and a second detector structure. The second source structureis arranged to be connected to a second radiation emitter via the cableinterface. The second detector structure is arranged to be connected toa second photodetector via the cable interface, where the secondradiation emitter and the second photodetector are external to theprobe.

A first distance is between the first source structure and the firstdetector structure. A second distance is between the first sourcestructure and the second detector structure. A third distance is betweenthe second source structure and the first detector structure. A fourthdistance is between the second source structure and the second detectorstructure. The first distance is not equal to the fourth distance andthe second distance is not equal to the third distance.

In various implementations, the marking mechanism output includes an inknozzle. The marking mechanism output is positioned within tenmillimeters of the first detector structure. The marking mechanismoutput is positioned within nine millimeters of the first detectorstructure. The marking mechanism output is positioned within eightmillimeters of the first detector structure. The marking mechanismoutput is positioned within seven millimeters of the first detectorstructure. The marking mechanism output is positioned within sixmillimeters of the first detector structure. The marking mechanismoutput is positioned within five millimeters of the first detectorstructure. The marking mechanism output is positioned within fourmillimeters of the first detector structure. The marking mechanismoutput is positioned within three millimeters of the first detectorstructure. The marking mechanism output is positioned within twomillimeters of the first detector structure.

Further, the marking mechanism output is connected to the sensor unit.The probe includes a handle, where the sensor unit is connected to thehandle, and a light emitting diode, also connected to a handle. Themarking mechanism output can also be connected to the handle.

In an implementation, a probe of a medical device includes: a firstretaining mechanism, to removably connect a sensor unit to the probe; afirst marking reservoir; a second retaining mechanism, to connect thefirst marking reservoir to the probe; and a marking mechanism, connectedto the first marking reservoir.

In a specific implementation, the second retaining mechanism removablyconnects the first marking reservoir to the probe. In thisimplementation, the marking reservoir is user replaceable, just as thesensor is user replaceable.

The second retaining mechanism can be internal to the probe, such asheld within or in a compartment of the probe. The first markingreservoir can have a transparent or see-through window, so the user cansee how much ink or other material is left.

The probe typically also includes an elongated handle, which a user cangrasp. The first marking reservoir, the second retaining mechanism, andthe marking mechanism are connected to this handle.

The first marking reservoir includes a first ink of a first color andthe probe further includes: a second marking reservoir including asecond ink of a second color, different from the first, where the secondmarking reservoir is coupled to the marking mechanism. A third retainingmechanism connects the second marking reservoir to the probe.

In a specific implementation, a method includes: transmitting a firstlight through a source structure into a target tissue; receiving asecond light transmitted through the target tissue at a detectorstructure; based on values for the first and second light, determiningan oxygen saturation value for the target tissue; and after thedetermining an oxygen saturation value, marking a tissue surfacerepresentative of a location of the target tissue.

Marking a tissue surface can include placing ink on the tissue surface.However, if the determining an oxygen saturation value does notsuccessfully obtain a result, the tissue surface is not marked. Afterthe determining an oxygen saturation value, the above method can furtherinclude turning on a light indicator at the probe.

In a specific implementation, a method includes: transmitting a firstlight through a source structure into a target tissue; receiving asecond light transmitted through the target tissue at a detectorstructure; based on values for the first and second light, determiningan oxygen saturation value for the target tissue; and after thedetermining an oxygen saturation value, marking a tissue surfacerepresentative of the oxygen saturation value.

The marking a tissue surface can include: when the oxygen saturationvalue is below a first threshold value, not marking the tissue surface;and when the oxygen saturation value is above the first threshold value,marking the tissue surface with a mark. The marking a tissue surface caninclude: when the oxygen saturation value is below a first thresholdvalue, marking the tissue surface with a first mark having a firstcharacteristic; and when the oxygen saturation value is above the firstthreshold value, marking the tissue surface with a second mark having asecond characteristic.

The marking a tissue surface can further include: when the oxygensaturation value is above a second threshold value (where the secondthreshold value is above the first threshold value), marking the tissuesurface with a third mark having a third characteristic. In animplementation, the first mark is an ink of a first color, the secondmark is an ink of a second color, and the third mark is an ink of athird color. The first, second, and third colors are visuallydistinguishable from each other.

In various implementations, the method further includes: when the oxygensaturation value is below the first threshold value, not turning on alight indicator used specially for a warning purpose and, when theoxygen saturation value is above the first threshold value, turning onthe light indicator. A variation of this method further includes: whenthe oxygen saturation value is below the first threshold value, turningon a first light indicator having a first characteristic; and when theoxygen saturation value is above the first threshold value, turning on asecond light indicator having a second characteristic.

Other objects, features, and advantages of the present invention willbecome apparent upon consideration of the following detailed descriptionand the accompanying drawings, in which like reference designationsrepresent like features throughout the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram of an oximeter system for measuring oxygensaturation of tissue in a patient.

FIG. 2 shows a more detailed block diagram of a specific implementationof the system of FIG. 1.

FIG. 3 shows a block diagram of an oximeter system incorporating amarking feature.

FIG. 4 shows marking a tissue using a drop.

FIG. 5 shows marking a tissue using a spray.

FIG. 6 shows marking a tissue using a stamp.

FIG. 7 shows a block diagram of an oximeter system incorporating amarking feature and LEDs.

FIG. 8 shows a block diagram of a marking probe which has a holder for asensor.

FIG. 9 shows a flow diagram for operating a tissue oximeter having amarking feature.

FIG. 10 shows a flow diagram for using multiple marking colors toindicate oxygen saturation levels.

FIG. 11 shows a flow diagram for using multiple LED colors to indicateoxygen saturation levels.

FIG. 12 shows a flow diagram for operating a tissue oximeter having amarking feature and LEDs.

FIG. 13 shows a sensor head and inker of an oximeter device.

FIG. 14 shows a handheld probe having a handle, sensor head, LEDs,inker, and ink boxes.

FIG. 15 shows a sensor opening pattern where one sensor opening isaligned asymmetrically with respect to the other sensor openings.

FIG. 16 shows another sensor opening pattern where one sensor opening isaligned asymmetrically with respect to the other sensor openings.

FIG. 17 shows a sensor opening pattern where the openings are arrangedsymmetrically about a vertical axis.

FIG. 18 shows another sensor opening pattern where one sensor opening isaligned asymmetrically with respect to the other sensor openings.

FIG. 19 shows a sensor opening pattern where the openings are arrangedsymmetrically about horizontal and vertical axes.

FIG. 20 shows a sensor opening pattern where the openings are aligned ina row.

FIG. 21 shows a sensor opening pattern where the openings are aligned ina row, except for one of the openings.

FIG. 22 shows a sensor opening pattern with two openings.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows an oximeter system 101 for measuring oxygen saturation oftissue in a patient. The system includes a system unit 105 and a sensorprobe 108, which is connected to the system unit via a wired connection112. Connection 112 may be an electrical, optical, or another wiredconnection including any number of wires (e.g., one, two, three, four,five, six, or more wires or optical fibers), or any combination of theseor other types of connections. In other implementations of theinvention, however, connection 112 may be wireless such as via a radiofrequency (RF) or infrared communication.

Typically, the system is used by placing the sensor probe in contact orclose proximity to tissue (e.g., skin or nerve) at a site where anoxygen saturation or other related measurement is desired. The systemunit causes an input signal to be emitted by the sensor probe into thetissue (e.g., human tissue). There may be multiple input signals, andthese signals may have varying or different wavelengths. The inputsignal is transmitted into or through the tissue.

Then, after transmission through or reflection off the tissue, thesignal is received at the sensor probe. This received signal is receivedand analyzed by the system unit. Based on the received signal, thesystem unit determines the oxygen saturation of the tissue and displaysa value on a display of the system unit.

In an implementation, the system is a tissue oximeter, which can measureoxygen saturation without requiring a pulse or heart beat. A tissueoximeter of the invention is applicable to many areas of medicine andsurgery including plastic surgery and spinal surgery. The tissueoximeter can make oxygen saturation measurements of tissue where thereis no pulse; such tissue, for example, may have been separated from thebody (e.g., a flap) and will be transplanted to another place in thebody.

Aspects of the invention are also applicable to a pulse oximeter. Incontrast to a tissue oximeter, a pulse oximeter requires a pulse inorder to function. A pulse oximeter typically measures the absorbancesof light due to the pulsing arterial blood.

There are various implementations of systems and techniques formeasuring oxygen saturation such as discussed in U.S. Pat. Nos.6,516,209, 6,587,703, 6,597,931, 6,735,458, 6,801,648, and 7,247,142.These patents are assigned to the same assignee as this patentapplication and are incorporated by reference.

FIG. 2 shows greater detail of a specific implementation of the systemof FIG. 1. The system includes a processor 204, display 207, speaker209, signal emitter 231, signal detector 233, volatile memory 212,nonvolatile memory 215, human interface device or HID 219, I/O interface222, and network interface 226. These components are housed within asystem unit enclosure. Different implementations of the system mayinclude any number of the components described, in any combination orconfiguration, and may also include other components not shown.

The components are linked together using a bus 203, which represents thesystem bus architecture of the system. Although this figure shows onebus that connects to each component, the busing is illustrative of anyinterconnection scheme serving to link the subsystems. For example,speaker 209 could be connected to the other subsystems through a port orhave an internal direct connection to processor 204.

A sensor probe 246 of the system includes a probe 238 and connector 236.The probe is connected to the connector using wires 242 and 244. Theconnector removably connects the probe and its wires to the signalemitter and signal detectors in the system unit. There is one cable orset of cables 242 to connect to the signal emitter, and one cable or setof cables 244 to connect to the signal detector. In an implementationthe cables are fiber optic cables, but in other implementations, thecables are electrical wires.

Signal emitter 231 is a light source that emits light at one or morespecific wavelengths. In a specific implementation, two wavelengths oflight (e.g., 690 nanometers and 830 nanometers) are used. In otherimplementations, other wavelengths of light may be used. The signalemitter is typically implemented using a laser diode or light emittingdiode (LED). Signal detector 233 is typically a photodetector capable ofdetecting the light at the wavelengths produced by the signal emitter.

The connector may have a locking feature; e.g., insert connector, andthen twist or screw to lock. If so, the connector is more securely heldto the system unit and it will need to be unlocked before it can beremoved. This will help prevent accidental removal of the probe.

The connector may also have a first keying feature, so that theconnector can only be inserted into a connector receptacle of the systemunit in one or more specific orientations. This will ensure that properconnections are made.

The connector may also have a second keying feature that provides anindication to the system unit which type of probe is attached. Thesystem unit may handle making measurements for a number of differenttypes of probes. When a probe is inserted, the system uses the secondkeying feature to determine which type of probe is connected to thesystem. Then the system can perform the appropriate functions, use theproper algorithms, or otherwise make adjustments in its operation forthe specific probe type.

For example, when the system detects a cerebral probe is connected, thesystem uses cerebral probe algorithms and operation. When the systemdetects a thenar probe is connected, the system uses thenar probealgorithms and operation. A system can handle any number of differenttypes of probes. There may be different probes for measuring differentparts of the body, or different sizes or versions of a probe formeasuring a part of the body (e.g., three different thenar probemodels).

With the second keying feature, the system will be able to distinguishbetween the different probes. The second keying feature can use any typeof coding system to represent each probe including binary coding. Forexample, for a probe, there are four second keying inputs, each of whichcan be a logic 0 or 1. With four second keying inputs, the system willbe able to distinguish between sixteen different probes.

Typically, probe 246 is a handheld tool and a user moves the probe fromone point to another to make measurements. However, in someapplications, probe 246 is part of an endoscopic instrument or roboticinstrument, or both. For example, the probe is moved or operated using aguiding interface, which may or may not include haptic technology.

In various implementations, the system is powered using a wall outlet orbattery powered, or both. Block 251 shows a power block of the systemhaving both AC and battery power options. In an implementation, thesystem includes an AC-DC converter 253. The converter takes AC powerfrom a wall socket, converts AC power to DC power, and the DC output isconnected to the components of the system needing power (indicated by anarrow 254). In an implementation, the system is battery operated. The DCoutput of a battery 256 is connected to the components of the systemneeding power (indicated by an arrow 257). The battery is rechargedusing a recharger circuit 259, which received DC power from an AC-DCconverter. The AC-DC converter and recharger circuit may be combinedinto a single circuit.

The nonvolatile memory may include mass disk drives, floppy disks,magnetic disks, optical disks, magneto-optical disks, fixed disks, harddisks, CD-ROMs, recordable CDs, DVDs, recordable DVDs (e.g., DVD-R,DVD+R, DVD-RW, DVD+RW, HD-DVD, or Blu-ray Disc), flash and othernonvolatile solid-state storage (e.g., USB flash drive),battery-backed-up volatile memory, tape storage, reader, and othersimilar media, and combinations of these.

The processor may include multiple processors or a multicore processor,which may permit parallel processing of information. Further, the systemmay also be part of a distributed environment. In a distributedenvironment, individual systems are connected to a network and areavailable to lend resources to another system in the network as needed.For example, a single system unit may be used to collect results fromnumerous sensor probes at different locations.

Aspects of the invention may include software executable code orfirmware (e.g., code stored in a read only memory or ROM chip). Thesoftware executable code or firmware may embody algorithms used inmaking oxygen saturation measurements of the tissue. The softwareexecutable code or firmware may include code to implement a userinterface by which a user uses the system, displays results on thedisplay, and selects or specifies parameters that affect the operationof the system.

Further, a computer-implemented or computer-executable version of theinvention may be embodied using, stored on, or associated with acomputer-readable medium. A computer-readable medium may include anymedium that participates in providing instructions to one or moreprocessors for execution. Such a medium may take many forms including,but not limited to, nonvolatile, volatile, and transmission media.Nonvolatile media includes, for example, flash memory, or optical ormagnetic disks. Volatile media includes static or dynamic memory, suchas cache memory or RAM. Transmission media includes coaxial cables,copper wire, fiber optic lines, and wires arranged in a bus.Transmission media can also take the form of electromagnetic, radiofrequency, acoustic, or light waves, such as those generated duringradio wave and infrared data communications.

For example, a binary, machine-executable version, of the software ofthe present invention may be stored or reside in RAM or cache memory, oron a mass storage device. Source code of the software of the presentinvention may also be stored or reside on a mass storage device (e.g.,hard disk, magnetic disk, tape, or CD-ROM). As a further example, codeof the invention may be transmitted via wires, radio waves, or through anetwork such as the Internet. Firmware may be stored in a ROM of thesystem.

Computer software products may be written in any of various suitableprogramming languages, such as C, C++, C#, Pascal, Fortran, Perl, Matlab(from MathWorks, www.mathworks.com), SAS, SPSS, JavaScript, AJAX, andJava. The computer software product may be an independent applicationwith data input and data display modules. Alternatively, the computersoftware products may be classes that may be instantiated as distributedobjects. The computer software products may also be component softwaresuch as Java Beans (from Sun Microsystems) or Enterprise Java Beans (EJBfrom Sun Microsystems).

An operating system for the system may be one of the Microsoft Windows®family of operating systems (e.g., Windows 95, 98, Me, Windows NT,Windows 2000, Windows XP, Windows XP x64 Edition, Windows Vista, WindowsCE, Windows Mobile), Linux, HP-UX, UNIX, Sun OS, Solaris, Mac OS X,Alpha OS, AIX, IRIX32, or IRIX64. Microsoft Windows is a trademark ofMicrosoft Corporation. Other operating systems may be used, includingcustom and proprietary operating systems.

Furthermore, the system may be connected to a network and may interfaceto other systems using this network. The network may be an intranet,internet, or the Internet, among others. The network may be a wirednetwork (e.g., using copper), telephone network, packet network, anoptical network (e.g., using optical fiber), or a wireless network, orany combination of these. For example, data and other information may bepassed between the computer and components (or steps) of a system of theinvention using a wireless network using a protocol such as Wi-Fi (IEEEstandards 802.11, 802.11a, 802.11b, 802.11e, 802.11g, 802.11i, and802.11n, just to name a few examples). For example, signals from asystem may be transferred, at least in part, wirelessly to components orother systems or computers.

In an embodiment, through a Web browser or other interface executing ona computer workstation system or other device (e.g., laptop computer,smartphone, or personal digital assistant), a user accesses a system ofthe invention through a network such as the Internet. The user will beable to see the data being gathered by the machine. Access may bethrough the World Wide Web (WWW). The Web browser is used to downloadWeb pages or other content in various formats including HTML, XML, text,PDF, and postscript, and may be used to upload information to otherparts of the system. The Web browser may use uniform resourceidentifiers (URLs) to identify resources on the Web and hypertexttransfer protocol (HTTP) in transferring files on the Web.

FIG. 3 shows a block diagram of a specific implementation of a system ofthe invention. This system can measure oxygen saturation of tissue andalso mark a location of where the measurement was made using a markingmechanism. This implementation includes a system console (or enclosure)300 and a probe 308. Typically, the probe is a handheld tool that isconnected to the system console through a connector (not shown).

The system console includes a computer or controller 311 that governsoperation of the system. Details of the console may be as discussedabove and shown in FIG. 2. For example, an emitter 314 is analogous tosignal emitter 231, and a detector 317 is analogous to signal detector233.

The computer is connected to (or incorporates) emitter 314, detector317, and a marking source 322. In an implementation, marking is by ink;in other implementations, however, other types of marking and theirassociated mechanisms may be used instead, or in combination with eachother.

Within the computer, there is an ink controller 325 that governsoperation of the inking mechanism. The ink controller functionality maybe incorporated in the computer controller functionality of the system.However, in other implementations, the ink controller may be separatefrom the computer, such as implemented using a separate integratedcircuit or chip.

The system probe includes a sensor 329 and an inker 333. The sensor ofthe probe is connected to the emitter and detector of the system consoleand the inker is connected to the ink source. Because the sensor andinker are part of the same probe, a location that the inker marks willgenerally be in proximity to the sensor. In a specific implementation,the inker is positioned within about 10 millimeters of one the sensors(e.g., an edge of an emitter or detector opening). In otherimplementation, the inker is position within about X millimeters of asensor, where X is any value such as 18, 17, 16, 15, 12, 9, 8, 7, 6,5.8, 5.5, 5, 4, 3, 2, or 1.

To measure oxygen saturation, the sensor of the probe is placed on atarget tissue 335 where a measurement is desired. Light is generated atthe emitter and transmitted through a connection 337 to the sensor. Thislight is scattered into the tissue and some light is reflected back tothe sensor, which is transmitted via a connection 341 to the detector.Based on the transmitted and received light, the computer (orcontroller) calculates the oxygen saturation of the tissue. A value canappear on a display (not shown) of the console.

After the oxygen saturation measurement is successfully made, the inkcontroller directs the inker (via the ink source) to mark the targettissue. The specific marking mechanism in this figure is an inkingmechanism. But, there are many other techniques and mechanisms formarking tissue, and any of these techniques may be used instead of, orin conjunction with, ink.

For example, some other marking techniques include using tattooing,dyes, pigments, stickers, chemicals, toner, acids, bases, ultraviolet,laser, infrared, radiation, etching, thermal, liquid, heat, burning,branding, and many others. One or more tissue marking techniques can beused in combination with each other.

The inking mechanism shown in this figure includes the ink controller,ink source, and inker. The ink controller determines when and how tomark the tissue. A controller can be implemented using an electroniccircuit (e.g., one or more integrated circuits) with the logic tocontrol the inking function. This logic can include combinatorial logic(e.g., NAND gates and NOR gates) or sequential logic (e.g., flip flops,registers, and state machines), or both. The controller can also beimplemented using software or firmware, which directs operations of aprogrammed machine (e.g., a computer).

The ink source is a reservoir of ink or other material used for markingthe tissue. The inker is, for example, a tip, nozzle, or head of theinking mechanism which emits the ink that marks the tissue.

The inker head can have any size, shape, or form. A larger-sized inkerwill generally make a larger mark, while a smaller-sized inker will makea smaller mark. If a smaller-sized inker is used, multiple marks may beused in order to increase its size or prominence. Some additionalexamples of forms of an inker include a sponge, a pipette, or a stamp.Some examples of shapes of an inker include rectangle, circle, dot,square, line drawing, or character (e.g., letter or symbol). An inkermay include any combination of sizes, forms, and shapes. For example,the inker may have multiple nozzles.

The inker can mark the tissue in a number of ways. Some specifictechniques are to drop a droplet of ink on the tissue (see FIG. 4),spray ink on the tissue (see FIG. 5), and stamp the tissue (see FIG. 6).Any of these or other marking techniques may be used. The specific markmade on the tissue is usually related to the shape or form of the inkerhead.

For example, when the inker is a circle stamp, then the resulting markwill be a circle on the tissue. If the inker is a nozzle, then the inkercan place multiple droplets in the form of a particular shape orcharacter. Additionally, the inker may mark using multiple droplets ofink on the tissue, such as two drops, three drops, four drops, or more.

In an implementation, the system provides a marking mechanism having asingle color, such as a single ink color. In an implementation, the inksource is a reservoir that holds a single ink color (such as black). Asdirected by the controller, ink is delivered from the ink source to theinker via a connection 343, which may be a tube. For example, ink may beforced out of the ink source to the inker head using a pressure pulse(such as caused by a piezoelectric material or pump).

In an implementation, there is only one cable interface which connects(i) the emitter and sensor, (ii) the detector and sensor, and (iii) theink source and inker. In an alternative implementation, there is morethan one connection interface. For example, there is a first cableinterface that has (i) and (ii) and a second cable interface that has(iii). As another example, there is a first cable interface that has(i), a second cable interface that has (ii), and a third cable interfacethat has (iii).

When the reservoir becomes low or empty, the user can refill thereservoir with additional ink or other material. The system may give avisual or audible indication on the screen of the console when thereservoir is low or the ink source needs to be replaced. It is desirablethat the ink is nontoxic, so it does not cause harm to the tissue orpatient.

In a specific implementation, the ink source is a replaceable inkcartridge, which can be disposed of after use. When an ink cartridge isempty, it may be removed from a receptacle of the console and replacedwith a like cartridge that is full. By using replaceable ink cartridges,users may replace ink with less likelihood of spilling ink during thereplacement process, especially compared to using an eye dropper totransfer ink from an ink bottle. Further, each cartridge may be sealedand have an expiration date, which ensures their effectiveness.

In another implementation, at the option of the user, used inkcartridges may be refilled and then used again. Or the cartridges can beremanufactured and then used again. This will help reduce the amount ofwaste going to landfills.

In another implementation, the system provides a marking mechanismhaving multiple colors, such as two or more ink colors. There can be anynumber of colors, two, three, four, five, six, seven, eight, or morecolors. Some examples of colors include red, green, blue, cyan, orange,magenta, yellow, and black. There can be various hues, tints, shades, orintensities of the same color. Ink for multiple colors can be refilledor replaced similarly as discussed above.

With multiple ink colors, there are multiple ink reservoirs, onereservoir for each ink color. Multiple colors of ink may also besupplied using multiple replaceable ink cartridges or a singlereplaceable cartridge including multiple colors. A disadvantage of usinga single replaceable cartridge having multiple colors is that when onecolor is used up, the entire cartridge will need to be replaced eventhough ink remains for one or more of the other colors.

For an implementation of the invention where there are multiple inkcolors, each ink color is derived an ink source that is connected via atube to an inker head. In one implementation, for each ink color, thereis one tube connecting an ink source to an inker head. So, for threecolors, there will be three tubes and three inker heads. However, in analternate implementation, there is a single inker head that receives inkfrom tubes connected to the different color ink sources.

FIGS. 4, 5, and 6 show three different ways of marking a tissue. Forexample, the marking may be at a tissue surface, above a location wherea measurement has been made. FIG. 4 shows an inker that drops ink ontothe surface of a tissue. FIG. 5 shows an inker spraying ink on thetissue. FIG. 6 shows an inker stamping the tissue. Any of thesetechniques of marking may be used individually, or they may be used inany combination with each other, or in combination with other markingtechniques.

For example, one marking variation involves using multiple drops on thesurface of a target tissue. Further, other marking techniques notspecifically discussed in this application may also be used inconjunction with the invention.

FIG. 7 shows a block diagram of another implementation of a system ofthe invention. This implementation is similar to the implementation inFIG. 3. Compared to the system in FIG. 3, there are two additionalcomponents: an LED controller 747 in the console 707 and LEDs 750, orother visible light sources, on the probe 716.

As discussed above, emitter 314 may be implemented using light sourcessuch as laser diodes and LEDs. In contrast to the light sources used foremitter 314, LEDs 750 and light sources are used as indicators for theuser and not used in measuring oxygen saturation.

Light from emitter 314 is transmitted to sensor into the tissue to bemeasured. Consequently, the sensor or emitter is usually on atissue-facing surface of the probe. When the probe is used, thetissue-facing surface and the sensor are generally hidden or not visibleby the user because this surface faces and touches (or is close to) thetissue surface. In contrast, LEDs 750 are positioned to be visible tothe user, even when the probe is used. Any indicator lights (e.g., LEDs750) are positioned on the probe on a surface other than or differentfrom the tissue-facing surface of the probe. Indicator lights will be ona non-tissue-facing surface. For example, LEDs 750 are positioned on aside, top, or near a handle of the probe. See FIG. 14 for an example ofpositioning of some LEDs.

Further, in an implementation, emitter 314 provides narrowband light ata specific wavelength. In comparison, LEDs 750 provide a wider band oflight (e.g., wide spectrum green, yellow, or red light). Also, the poweroutput of emitter 314 will generally be higher at the specificwavelength than provided by a wider band light source such as LED 750.For example, in an implementation, the power output of emitter 314 isabout 3 milliwatts at the particular wavelength (e.g., 690 nanometers or830 nanometers). Emitter 314 typically provides greater power output,especially at the desired wavelength, than one LED 750.

For visible light, violet light has a wavelength band from 380nanometers to 450 nanometers. Blue light has a wavelength band from 450nanometers to 495 nanometers. Green light has a wavelength band from 495nanometers to 570 nanometers. Yellow light has a wavelength band from570 nanometers to 590 nanometers. Orange light has a wavelength bandfrom 590 nanometers to 620 nanometers. Red light has a wavelength bandfrom 620 nanometers to 750 nanometers.

Infrared-A light has a wavelength band from about 700 nanometers to 1400nanometers. Infrared-B light has a wavelength band from about 1400nanometers to 3000 nanometers. Infrared-C light has a wavelength bandfrom about 3000 nanometers to 1 millimeter. Light having a wavelength of830 nanometers is not visible.

In an implementation, emitter 314 is located within the console, whileLEDs 750 are located at the probe. In another implementation, emitter314 is located on a tissue-facing surface of the probe, while LEDs 750are located on a non-tissue-facing surface of the probe.

In an implementation, an oxygen saturation measurement is made and thenLEDs 750 are illuminated (or turned off—when using negative Booleanlogic) to give an indication of the measured oxygen saturation.Therefore, emitter 314 is turned on before LEDs 750 will give anindication of the measured oxygen saturation by either turning on orturning off LEDs 750.

In an implementation (i.e., positive Boolean logic), emitter 314 andLEDs 750 will not be turned on at the same time. In an implementation(i.e., negative Boolean logic), emitter 314 will not be on at the sametime LEDs 750 are off.

In contrast to emitter 314, LEDs 750 can be activated in many differentways. For example, in an implementation, a system uses one thresholdoxygen saturation value in determining whether to activate one LED. Ifthe obtained oxygen saturation measurement falls below the thresholdvalue, then the LED is not turned on. If the obtained oxygen saturationmeasurement is above the threshold value, then the LED is turned on.Thus, activation of LED 750 depends solely upon the oxygen saturationmeasurement value. LEDs 750 are not involved in obtaining themeasurement.

In another implementation, there are two LEDs. If an oxygen saturationmeasurement falls below a threshold value, a first LED is activated. Thefirst LED may, for example, emit yellow light. If an oxygen saturationmeasurement falls above a threshold value, a second LED is activated.The second LED may emit green light.

Thus, LEDs 750 can have multiple characteristics. For example, they canemit multiple colors. In another implementation, the LEDs can use avariety of flashing mechanisms. In various implementations, LEDs 750provide a greater number of colors than emitter 314. LEDs 750 provideonly visible light while emitter 314 provides not visible light. LEDs750 provide only visible light while emitter 314 provides not visiblelight and visible light. LEDs 750 are larger in size then emitter 314.LEDs 750 are smaller in size then emitter 314. There are greater numbersof LEDs 750 than emitters 314. There are greater numbers of emitters 314than LEDs 750.

Although LEDs or light emitting diodes are specifically shown anddiscussed, other implementations of the invention may use other lightingor visualization techniques and means. Some examples include lightbulbs, organic LEDs (OLEDs), plasma, LCD, fluorescent tube, andelectroluminescent material. Some visualization techniques do not useactive light emitters, but rely on ambient lighting; some examplesinclude electronic paper and an LCD without backlighting.

The LED controller and LEDs, or other visible light sources, arecomponents of a visual indication mechanism. The LED controller governsoperation of this mechanism. As discussed above, such a controller maybe implemented using electronic circuitry. The LED controllerfunctionality may be incorporated in the computer controllerfunctionality of the system as shown in FIG. 7. However, in otherimplementations, the LED controller may be separate from the computer,such as implemented using a separate integrated circuit or chip.

The LED controller determines when and how to activate the visible lightsource. The LED controller is connected to and activates the visiblelight source of the system probe via an electrical connection 753,typically a wire or cable.

The LEDs, or other visible light sources, on the probe arelight-emitting diodes or other light source that emit visible light onceactivated by the LED controller. In a system, there can be any number ofLEDs, one, two, three, four, or more than four. In the case where thereare multiple LEDs, in addition to a power and ground connection to eachLED, there may be a single wire from the controller to connect to eachLED. The wires can be incorporated in a cable carrying all the LEDwiring; additionally, this cable may also include the wiring to thesensor and inker.

The LED controller will activate and light the visible light sourcebased on any number of preprogrammed factors or user-selected factors.For example, the visible light sources can be used to flash, thusindicating a system error condition, battery low condition, low inksource condition, connector error condition, or other conditions.

In a specific implementation, the lighting of the LEDs is based onoxygen saturation measurements determined by the system console. In thisimplementation, the LEDs, or other visible light sources, are located onthe probe of the system in order to make the visual indication of tissueoxygen saturation convenient for the user of the system to see.

In an alternative implementation, the visual indication (the LEDs orother visible light sources) is placed on or near the system console.However, for such an implementation, it may be more difficult orinconvenient for the user to see the visual indication because theconsole may be located some distance away from the user and patient.

Having the LEDs on the probe, as illustrated in this figure, improvesthe efficiency of verifying the oxygen saturation calculated by thesystem console in that the system user can see the visual indicationwhile applying the sensor of the system probe to the patient's tissue.Placement of the LEDs, or other visible light sources, on the probe alsoallows the system user to verify that the inker marks the tissue in amanner that corresponds to the particular activation of the LEDs.

There may be one or multiple (two or more) visible light sources andeach visible light source may be of any size. Generally, the larger thevisible light source, the easier it will be for the system user to see.However, if a smaller-sized visible light source is used, multiplevisible light sources may be placed in a closely-spaced arrangement sothat, when the arrangement is activated, the combination ofsmaller-sized visible light sources may increase their visibility.

Additionally, the visual indication of an LED, or other visible lightsource, may take the form of any shape or character (i.e., a letter orsymbol) via placement of a cover or mask over the LEDs. Some examples ofshapes of a light cover include a rectangle, circle, triangle, orsquare. The LEDs may also take any combination of sizes and forms. Forexample, an LED may in the form of a large square, a small rectangle, orfour small circles in close proximity to each other to increase theirvisibility. A segmented or custom LED or LCD display panel may also beused.

One or more LEDs may be placed anywhere on the probe. For example, oneor more visible light sources can be located on the end of the probethat is closest to the sensor and inker. Conversely, one or more visiblelight sources can be located closer to the handle of the probe, orsomewhere in between.

If there are multiple LEDs, they may be arranged in any formation. Someexamples of various formations include a cluster, a row, a column, orother linear formation. Multiple LEDs can also be arranged to form acertain shape, such as a square, rectangle, circle, or triangle.

When activated by the LED controller, the visible light sources on thesystem probe can emit light via any signaling mechanism. For example,the LEDs will flash when activated (e.g., rapid flashing, short flasheswith a pauses between flashes, three flashes and a pausing beforerepeating this pattern, and flashing according to any pattern orfrequency). Conversely, they can stay lit for an extended period oftime, such as until marking by the marking mechanism (detailed in thedescription of FIG. 3) is complete. Any combination of signalingmechanisms may be incorporated into this system.

In a specific implementation, the system of the invention provides avisual indication mechanism where there is only one LED on the systemprobe. One visible light source may emit one color or multiple colors,such as two, three, four, or more.

In an implementation of one LED on the system probe, an LED may emit asingle color, such as blue light. When directed by the computer, the LEDcontroller may activate the LED on the probe, causing the LED to emitblue light.

In another implementation of one visible light source on the systemprobe, the visible light source may be capable of emitting multiple (twoor more) colors and may emit each color at a different time, dependingupon the direction provided by the LED controller. There may be anynumber of colors. Some examples of colors include blue, green, red,orange, and yellow. There may be various hues, tints, shades orintensities of the same color.

In a specific implementation, the system of the invention provides avisual indication mechanism with multiple visible light sources on thesystem probe. There may be any number of visible light sources: two,three, four, five, six, or more visible light sources. Multiple (two ormore) visible light sources may be used to emit one color or multiplecolors.

In an implementation of multiple LEDs on the system probe, a single LEDcolor, such as green, may be used. If the LEDs are small in size,multiple LEDs may be used to increase their visibility. For example, theLED controller may activate four small LEDs arranged, for example, in acluster on the probe, causing each of the LEDs to emit green light. Analternative implementation, for example, may involve three large LEDsthat emit green light. In this example, the LED controller may determinethe number of LEDs (one, two, or all three) to activate depending oninformation received by the system computer.

In another implementation of multiple LEDs on the system probe, each LEDmay correspond to a particular color. It may be desirable to havemultiple (two or more) LEDs, then, when multiple colors are used. TheLED controller may activate one LED (i.e., an LED that emits one color,such as blue light) at one point in time and a different LED (i.e., adifferent LED that emits a different color, such as green light) at adifferent point in time, or multiple LEDs (i.e., an LED that emits bluelight and a different LED that emits green light) at the same time. TheLED controller may activate any LED at any time and may alternatebetween LEDs or continue to activate the same LED, depending upondirection from the system computer. A given LED may emit any color inany hue, tint, shade or intensity of that color.

FIG. 8 shows a block diagram of a marking probe which has a holder for asensor 807, a marking source 819, and a marking mechanism 830. Theholder has a retaining mechanism (e.g., a retaining clip, clamp, orcavity) where a sensor unit of an oximeter (e.g., sensor 329) can beattached. The sensor unit may a small rectangular block with a cable.The probe is typically a handheld unit and includes a handle (see FIG.14).

One implementation of the retaining mechanism involves a clamp, clip, orband. For example, the holder may incorporate a clamp that grasps thesensor. To remove the sensor from the probe, the clamp may be released.The sensor is removably connected to the probe, which means the user canattach the probe and remove it from the probe as desired. Since thesensor is removable, the sensor can be disposed after it is worn out orafter use on a particular person. Then the probe can be used again withanother sensor.

In an implementation, this marking probe is used in conjunction with asystem unit or console, such as shown in one of the previous figures anddescribed above. There is a cable that connects to the sensor in theholder (indicated by two arrows in the figure) and a cable that connectsto the ink source (also indicated by an arrow). These components of theprobe are connected via a cable to the console as discussed above.

For this implementation, the system console calculates an oxygensaturation measurement for a tissue and displays the measurement valuevia the console display. In addition, the marking probe marks the tissuesuch that the tissue mark corresponds to the oxygen saturationmeasurement shown on the computer display.

In an implementation, the marking probe is a standalone marking probe,which means that it is can be used without necessarily attaching it to asystem unit or console. This standalone marking probe incorporates thecircuitry necessary to calculate oxygen saturation measurements anddetermine marking mechanism outputs. The sensor is connected to thecircuitry within the probe (e.g., the probe includes the light emitterand light detector). In use, the user will receive an indication on themeasured oxygen saturation via the marking mechanism and the display ofthe console is not needed.

For example, a user can identify an oxygen saturation measurement of atissue by looking at a mark on the tissue. Specifically, an oxygensaturation measurement above 80 percent may yield a green tissue mark.Thus, by looking at the green tissue mark, the user knows the oxygensaturation of the tissue is in an acceptable range without having tolook at a computer system display.

There are many different structures and mechanisms that can be used toallow the sensor to removably attach to the holder and probe. Forexample, in an implementation, the sensor casing has a built-in tab orother similar retaining feature that locks the sensor in place in theholder. One can press the tab and to release the sensor from the probe.Or a button may be pushed to release the sensor from the holder.

In another implementation of the retaining mechanism, a sensor unit isplaced into a cavity of the probe and latched in place. The sensor unitcan be removed from the probe by unlatching and pulling it out of thecavity.

Also, this figure shows the marking source located within the probe;however, in another implementation, the marking source is external tothe probe. Then, the ink source is connected to the inker of the probevia a cable (not shown). This implementation is more similar to probe308 of FIG. 3.

Further, the marking source may be removably attached to the probe,similar to how the sensor is removably attached. Any structure orretaining mechanism that allows the marking source to be removablyattached to the probe can be used. Then when the ink source runs out ofink, the user can remove an ink cartridge and replace it.

In another implementation, the marking source is not user replaceable.For this implementation, it is intended that once the ink has run out,the user will dispose of the probe and use a new probe. Therefore, theprobe itself is disposable, and the sensor for the probe is disposabletoo. In this case, for each use of one probe, a user may use and disposeof a number of sensor units. For example, the individual sensor unitsare used one per patient. And the probe is used until the ink runs out.

Marking material is delivered from marking source 819 to markingmechanism 830 via a connection 836. In the case of ink, connection 836is typically a tube or capillary to deliver ink. For example, markingmaterial may be forced out of the marking source to the markingmechanism using a pressure pulse (such as caused by a piezoelectricmaterial or pump).

In another implementation, there are multiple (two, three, four, ormore) ink reservoirs for multiple ink colors, such as blue, purple, andorange. In this implementation, if the blue ink runs out, the user maydispose and replace the blue ink reservoir. Conversely, if the inkreservoirs are contained in a single unit, the user may have to disposeof the entire ink reservoir unit even if the purple and orange inkreservoirs have not run out.

In an implementation, the marking mechanism may be disposable after eachuse. For example, the marking mechanism can be integrated with thesensor unit. In a specific implementation, the marking mechanism is aninking mechanism. An implementation involves disposing of the inkingmechanism after each use within one procedure; another implementationinvolves disposing of the marking mechanism after one entire procedureis completed.

FIG. 9 is a flow diagram of a marking feature of the invention which canbe incorporated into a system designed to measure oxygen saturation oftissues. In this specific implementation, the marking feature is aninking feature that enables marking of a tissue surface with one inkcolor.

First, in step 903, a user applies a tissue oximeter probe to a targettissue. The user may be a doctor or any other medical professional.Typically, the user, who wishes to determine the oxygen saturation of aparticular tissue, may apply a sensor of the tissue oximeter probe tothe surface of the skin in order to obtain this measurement.

When the sensor touches or is in contact with the target tissue, in step911, a computer (or controller) directs an emitter (connected to thesensor and computer) to transmit light to the sensor of the probe, andinto the target tissue. After the light is transmitted into the tissue,some of the light is reflected off of the tissue.

In step 915, a detector (connected to the sensor and computer) detectsthe light reflected off of the target tissue; this information isreceived at the sensor of the probe. The detector then sends this lightinformation to the computer.

The computer, in step 919, calculates the oxygen saturation of thetarget tissue using this light information. Then, the computer directsan ink controller to activate an ink source which connects to an inker.

In step 925, the inker marks the tissue surface with ink. Thisimplementation of this inking feature involves the application of anycolor to the surface of the target tissue. The inking feature may beused represent a tissue location. A single ink color may also be used,for example, to identify a location of the tissue where the oxygensaturation is at critically low levels, or at normal levels. A singleink color may essentially be used for any identification purposes.

For example, a mark is made when the oxygen saturation measurement islow, and no mark is made when the oxygen saturation measurement issatisfactory. Then the doctor will have a map of where the oxygensaturation readings are not at acceptable levels.

A variation of this implementation involves the use of a single inkcolor, such as black, and a marker capable of marking a tissue in two,three, four, or more ways, such as with multiple shapes or droplets. Forinstance, black squares can indicate low oxygen saturation levels of atissue, while black triangles represent elevated oxygen saturationlevels of the tissue. One drop represents one thing, while two dropsrepresent another.

FIG. 10 shows a flow diagram of an inking feature which can beincorporated into a system designed to measure oxygen saturation oftissues. This inking feature allows for the use of multiple ink colorsin marking the surface of a target tissue, where each color correspondsto a particular oxygen saturation range.

The oxygen saturation range may be selected by the user or predeterminedby the factory. Depending on the oxygen saturation level of the targettissue, a particular ink color will be used to mark the surface of thetarget tissue.

The ranges may be specified using threshold values, each of which may befactory set or user specified. For example, a user may enter thresholdvalues for when a mark (perhaps of a certain color) should be made, suchas through a touch screen of the console. Although this applicationgives some specific examples of values for the thresholds (e.g., 30percent and 40 percent) the values may be Z percent and A percent, whichare any number, where A is greater than Z.

In a specific implementation, the initial process of taking an oxygensaturation measurement and marking the tissue surface is exactly thesame as that presented in FIG. 9 (steps 903 through 925). However, inthis implementation, step 1028 shows that the inker marks the tissuesurface with colored ink based on the oxygen saturation value determinedby the computer.

As an example of this implementation, in step 1030, if the oxygensaturation is less than Z percent, then in step 1033, an inker marks thesurface of a tissue in an ink of a first color. Specifically, forexample, if the oxygen saturation is less than 30 percent, then an inkermarks a tissue surface with red ink.

If the oxygen saturation is not less than Z percent, then the computerconsiders step 1035. In step 1035, if the oxygen saturation is between Zpercent and A percent, then, in step 1038, an inker marks a tissuesurface in an ink of a second color, where the second color is differentfrom the first color. For example, if the oxygen saturation is between30 percent and 40 percent, then an inker marks a tissue surface inyellow ink.

If the oxygen saturation is not less than A percent and, thus, does notfall under steps 1030 or 1035, then the computer considers step 1040.

In step 1040, if the oxygen saturation is greater than A percent, then,in step 1043, an inker marks a tissue surface with an ink of a thirdcolor, where the third color is different from the first and secondcolors. For example, if the oxygen saturation is greater than 40percent, then an inker marks a tissue surface in green ink.

In a specific implementation, any color can be used and the thresholdvalues can be any number. Although in this implementation 30 percent and40 percent are used as examples of threshold values, any percentage,range, or number may be used as a threshold value in anotherimplementation.

One implementation may involve the use of one threshold value. Oxygensaturation levels falling at or below that value initiate the use of onecolor while oxygen saturation levels falling above that value initiatethe use of another color.

The oxygen saturation ranges need not be equal. For instance, blue inkmay be used when oxygen saturation levels fall at or below 20 percentand black ink may be used when oxygen saturation levels fall above 20percent.

A variation of this implementation involves the use of two equal rangeswhere blue ink is used for oxygen saturation values at or below 50percent and black ink is used for oxygen saturation values above 50percent.

Yet another implementation may involve the use of four threshold valuesand five corresponding colors. Any number of threshold values andcorresponding colors may be used. For example, there may be twothreshold values and three corresponding colors, five threshold valuesand six corresponding colors, or more.

The use of multiple ink colors has diverse applications. For instance,various areas of one tissue may be easily identifiable through the useof multiple colors, with each color representing a corresponding oxygensaturation measurement of that particular tissue area. Similarly,multiple tissues of various areas can be identified with differentcolors depending upon their respective oxygen saturation measurements.

A variation of this implementation involves the use of multiple colors,in combination with multiple marking techniques. For instance, a bluesquare may represent low oxygen saturation levels of a tissue, while anorange circle represents elevated oxygen saturation levels of thetissue.

FIG. 11 shows a flow diagram for the activation of LEDs, or othervisible light sources, which may be incorporated into a probe of asystem designed to measure oxygen saturation of tissues. Thisimplementation allows for the use of multiple LEDs, with each LED colorcorresponding to a particular range or value of the target tissue'soxygen saturation. Depending on the oxygen saturation level of thetarget tissue, a particular LED color will be turned on.

Similar to FIG. 9, in step 1103, a user applies a tissue oximeter probeto a target tissue

In steps 1106 and 1109, the computer receives the light information (viathe emitter and detector) from the sensor touching the target tissue.Using the light information, in step 1112, the computer then determinesthe oxygen saturation of that tissue and activates an LED controllerwhich, in step 1115, activates the LEDs (or other visible light sources)on the probe.

The ranges may be specified using threshold values, each of which may befactory set or user specified. For example, a user may enter thresholdvalues when an LED be turned on, such as through a touch screen of theconsole. Although this application gives examples of specific values forthe thresholds (e.g., 30 percent and 40 percent) the values may be G andS, which are any number, where S is greater than G.

In a specific implementation, in step 1118, if the oxygen saturation isless than G percent, then, in step 1120, an LED (or other visible lightsource) emits light of a first color. For example, if the oxygensaturation is less than 30 percent, then a red LED turns on. If theoxygen saturation is not less than G percent, then the computerconsiders step 1123.

In step 1123, if the oxygen saturation is between G percent and Spercent, then, in step 1125, an LED (or other visible light source)emits light of a second color, where the second color is different fromthe first color. For example, if the oxygen saturation is between 30percent and 40 percent, then a yellow LED turns on. If the oxygensaturation is not less than S percent and, thus, does not fall understeps 1118 or 1123, then the computer considers step 1128.

In step 1128, if the oxygen saturation is greater than S percent, then,in step 1130, an LED (or other visible light source) emits light of athird color, where the third color is different from the first andsecond colors. For example, if the oxygen saturation is greater than 40percent, then a green LED turns on.

In this implementation, an LED can emit any color and the thresholdvalues can be any number or range. As discussed above in the descriptionfor FIG. 10, the threshold percentages of 30 percent and 40 percent areused as examples; in other implementations, other threshold values maybe used.

This implementation may involve the use of one LED, or other visiblelight source, corresponding to one color. In such an implementation, asingle LED color, such as blue, may be used to identify a location ofthe tissue where the oxygen saturation is at critically low levels, orat normal levels. A single LED color may essentially be used for anyidentification purposes.

In a variation of an implementation with one LED, or other visible lightsource, on the system probe, a single LED color may also indicatemultiple conclusions when used in combination with various signalingmechanisms. For instance, an LED that emits blue light via a rapidflashing mechanism may represent critically low oxygen saturation levelsof a tissue while an LED that emits blue light for an extended period oftime may represent critically elevated oxygen saturation levels of thetissue.

In another variation of an implementation of one LED on the systemprobe, the LED, or other visible light source, may be capable ofemitting multiple colors at different times, depending upon the oxygensaturation of a tissue (calculated by the system console). For instance,when the oxygen saturation of a tissue is low, the LED may emit bluelight; when the oxygen saturation of a tissue is high, the same LED mayemit orange light.

This implementation may also involve the use of two LEDs, or othervisible light sources, each corresponding to a different color. In suchan implementation, as with the inking function described in FIG. 9, eachLED color corresponds to a particular range of oxygen saturation. Theranges need not be equal and there may be multiple ranges and thresholdvalues, thus leading to the use of multiple LED colors. Yet anotherimplementation may involve the use of five LEDs with each LEDcorresponding to a different color. The use of multiple LED colors,similar to the use of multiple ink colors in FIG. 9, has diverseapplications.

FIG. 12 shows a flow diagram of the inking feature (or other markingfeature) and LEDs (or other visible light sources), incorporated into adevice that measures oxygen saturation of tissues. Depending on theoxygen saturation of a target tissue, a particular LED color may turn onand a corresponding ink color may be used to mark the surface of atarget tissue.

Similar to FIGS. 9 and 11, in step 1203, a user applies a tissueoximeter probe to a target tissue. Then, in step 1211, an emittertransmits light to a sensor of a probe, and into the tissue. As some ofthe light is then reflected off of the tissue, in step 1215 a detectordetects the reflected light; this light information is received at thesensor of the probe.

In step 1219, a computer, which connects to the emitter and detector,uses this light information to calculate the oxygen saturation of thetarget tissue.

Similar to FIG. 11, the computer then activates an LED controller whichconnects to LEDs, or other visible light sources, on the probe and, instep 1222, turns a visible light source on based on the oxygensaturation of the target tissue. One, two, three, or more LEDs may beused.

Additionally, similar to FIG. 10, the computer directs an ink controllerto activate an ink source which connects to an inker. In step 1225,using the probe, the inker then marks the surface of the target tissuewith ink based on the oxygen saturation of that tissue.

There may be various combinations of this implementation of the markingand visual indication mechanisms incorporated into an oximeter orsimilar medical device. For example, there may one LED (or other visiblelight source) and one ink (or other mark) color. Variations may includeone LED and multiple ink colors, multiple LEDs and one ink color, ormultiple LEDs and multiple ink colors.

FIG. 13 shows an implementation of an inking mechanism connected to asensor head of an oximeter. Once the oxygen saturation of a targettissue is determined, ink supply tubes provide red, yellow, or green inkto an inker, which then marks the surface of a target tissue torepresent a location of a tissue and indicate an oxygen saturationmeasurement of the target tissue.

FIG. 14 shows an implementation of an oximeter probe with inkingmechanism. This probe includes visible light indictors sources on aprobe of the oximeter. This probe may be a standalone probe or a probethat is to be connected to an oximeter console. This oximeter probe hasan elongated handle allowing a user to more easily grasp the probe.

Depending upon an oxygen saturation measurement of a target tissue, ared, yellow, or green LED turns on. The color emitted by the LEDcorresponds with red, yellow, or green ink used to mark the surface of atarget tissue. In other implementations, the ink colors of the mark donot necessarily match the colors of the indicators lights.

Further, within the handle are ink boxes or cartridges (e.g., red,yellow, and green) that are connected via a tube to an inker. In animplementation, there is only one ink for one ink color. In otherimplementations, the ink color of the mark is a mixture of the inksprovided by the cartridges. For example, an orange color is obtained bycombining red and yellow.

The ink boxed may be contained within the probe handle or attached tothe probe handle. The probe may have an internal compartment thatencloses the ink boxes. Further there may be translucent window to theink boxes, so the user can visibly check the level of ink that is stillavailable. In an implementation, the probe is disposable and is replacedwith another probe when the ink boxes become empty. In animplementation, when the ink boxes become empty, the user can refillthem.

The inker is held in proximity (e.g., within 10 millimeters) or adjacentto the sensor head. In some implementations, the inker may be held afixed distance away form the sensor head; so when measurements and marksare made, one can look at the mark and find the location where a measurewas made.

FIGS. 15-22 show various specific implementations of a sensor unit orsensor head. Each figure shows a particular opening pattern, and any ofthese may be used in conjunction with any of the implementationsdiscussed in this patent. For example, a marking mechanism output may bepositioned to be in proximity to a sensor unit or attached to the sensorunit. These figures show only some examples of opening patterns. Thereare other possible opening patterns and any of these other openingpatterns, and their variations, may be used with the invention.

The sensor openings at the sensor head are typically connected via afiber optic cable to the emitters and detectors of the console. Theemitters are connected to a source sensor opening, and the detectors areconnected to a detector sensor opening. However, in an implementation,the emitter and detectors are positioned at the sensor head and a fiberoptic cable is not needed.

FIG. 15 shows a specific implementation of a sensor unit. Such a sensorunit may be incorporated in the various probe implementations (e.g.,sensor 329 or sensor for holder 807) discussed above in thisapplication.

This sensor has six openings 1501-1506. Openings 1501-1504 are arrangedin a line closer to a first edge of the sensor, while openings 1505 and1506 are arranged closer to a second edge, which is opposite the firstedge. In fact, opening 1506 is closer than opening 1505 to the secondedge. These openings are for sources and detectors, and there can be anynumber of sources, any number of detectors, and they can be in anycombination. In an implementation of a sensor head, the first edge isdistal to the second edge, which is closer to a cable attached to theprobe or hand holding the probe.

In one implementation, openings 1501-1504 are detectors while openings1505 and 1506 are sources. However, in other implementations, there canbe one or more detectors, two or more detectors, one or more sources, ortwo or more sources. For example, there may be three detectors and threesources or one detector and five sources.

In FIG. 15, the openings are positioned asymmetrically such that a linedrawn through openings 1501-1504 is not parallel to a line drawn throughopenings 1505 and 1506. However, a line drawn through openings 1501 and1505 is parallel to a line through openings 1504 and 1506. Additionally,the distance between openings 1501 and 1504 is shorter than the distancebetween openings 1505 and 1506.

Thus, the distance between openings 1501 and 1505 does not equal thedistance between openings 1501 and 1506; the distance between openings1502 and 1505 does not equal the distance between openings 1503 and1505; and the distance between openings 1503 and 1505 does not equal thedistance between openings 1504 and 1506.

In this implementation, the sensor unit has a rectangular shape, but thesensor unit may have any shape such a trapezoid, triangle, dodecagon,octagon, hexagon, square, circle, or ellipse. A sensor of any shape orform can incorporate the sensor openings in the pattern shown anddescribed.

In a specific implementation, a distance between openings 1501 and 1504is five millimeters. A distance between each of the openings 1501, 1502,1503, and 1504 is 5/3 millimeters. A distance between 1501 and 1505 isfive millimeters. A diameter of an opening is one millimeter.

FIG. 16 shows a variation of the implementation of the sensor unit shownin FIG. 15. The sensor unit in this specific implementation is alsoarranged to include six openings 1601-1606. Similar to FIG. 15, openings1601-1604 are arranged in a line closer to a first edge of the sensor,while openings 1605 and 1606 are arranged closer to a second edge, whichis opposite the first edge. In one implementation, openings 1601-1604are detectors while openings 1605 and 1606 are sources.

In this figure, the openings are positioned so that a line drawn throughopenings 1601-1604 is parallel to a line through openings 1605 and 1606.However, a line drawn through openings 1601 and 1605 is not parallel toa line through openings 1604 and 1606.

Additionally, similar to FIG. 15, the distance between openings 1601 and1604 is shorter than the distance between openings 1605 and 1606. Thus,the distance between openings 1601 and 1605 does not equal the distancebetween openings 1601 and 1606; the distance between openings 1602 and1605 does not equal the distance between openings 1603 and 1605; and thedistance between openings 1603 and 1605 does not equal the distancebetween openings 1604 and 1606.

In this implementation, the sensor unit itself is of a greater arearelative to the area of the sensor unit shown in FIG. 15. In anotherimplementation, the sensor unit may be of a smaller area relative to thearea shown in FIG. 15. In yet another implementation, the sensor unitmay be of a greater area relative to that shown in FIG. 16.

Further, in a specific implementation, the openings are the same size aseach other (e.g., each opening has the same diameter or each opening hasthe same area). A specific implementation uses one-millimeter circularopenings. However, in another implementation, the diameter of oneopening may be different from other openings, or there may be someopenings with different diameters than other openings. There can be anycombination of differently sized openings on one sensor unit. Forexample, there are two openings with a C size and other openings have aD size, where C and D are different and D is greater than C. Also,openings are not necessarily circular. So, C and D may represent areavalues.

FIG. 17 shows another variation of the implementation of the sensor unitshown in FIG. 15. The sensor unit in this specific implementation isalso arranged to include six openings 1701-1706. Similar to FIGS. 15 and16, openings 1701-1704 are arranged in a line closer to a first edge ofthe sensor, while openings 1705 and 1706 are arranged closer to a secondedge, which is opposite to the first edge. In one implementation,openings 1701-1704 are detectors while openings 1705 and 1706 aresources.

In this figure, the openings are positioned so that a line drawn throughopenings 1701-1704 is parallel to a line through openings 1705 and 1706.In fact, these two lines are equal in length. Furthermore, a line drawnthrough openings 1701 and 1705 is parallel (and equal in length) to aline through openings 1704 and 1706.

Thus, in this specific implementation, the distance between openings1701 and 1706 is equal to the distance between openings 1704 and 1705.This specific arrangement includes further equalities: the distancebetween openings 1702 and 1705 equals that between openings 1703 and1706 and the distance between openings 1703 and 1705 equals that betweenopenings 1702 and 1706.

In an implementation, the distances between openings 1701-1704,1704-1706, 1706-1705, and 1705-1701 are all equal; thus, in thisimplementation openings 1701, 1704, 1706, and 1705 form the vertices ofa square. In other implementations, however, four openings may form thevertices of any quadrilateral, such as a rectangle, a rhombus, atrapezoid, or a parallelogram.

Aside from the equalities mentioned, the distances between each of theopenings 1701-1704 and each of the openings 1705-1706 are not equal. Forinstance, the distance between openings 1701 and 1705 does not equal thedistance between openings 1701 and 1706.

FIG. 18 shows a specific implementation of a sensor unit which isarranged to include four openings 1801-1804. Openings 1801 and 1802 arearranged in a line closer to a first edge of the sensor, while openings1803 and 1804 are arranged closer to a second edge, which is oppositethe first edge. In fact, opening 1804 is closer than opening 1803 to thesecond edge. In an implementation the first edge is distal to the secondedge, which is closer to a cable attached to the probe or hand holdingthe probe.

In one implementation, openings 1801 and 1802 are detectors and openings1803 and 1804 are sources. However, in other implementations, there canbe one or more detectors, two or more detectors, one or more sources, ortwo or more sources. For example, there may be three detectors and onesource or one detector and three sources.

In FIG. 18, the openings are positioned asymmetrically such that a linedrawn through openings 1801 and 1802 is not parallel to a line throughopenings 1803 and 1804. However, a line drawn through openings 1801 and1803 is parallel to a line through openings 1802 and 1804.

Additionally, the distance between openings 1801 and 1802 is shorterthan the distance between openings 1803 and 1804. Thus, in FIG. 18, thedistance between openings 1801 and 1803 does not equal the distancebetween openings 1802 and 1804 and the distance between openings 1802and 1803 does not equal that between openings 1802 and 1804.

FIG. 19 shows a variation of the implementation of the sensor unit shownin FIG. 18. The sensor unit of this implementation also includes fouropenings 1901-1904. Openings 1901 and 1902 are arranged in a line closerto a first edge of the sensor, while openings 1903 and 1904 are arrangedcloser to a second edge, which is opposite the first edge. In oneimplementation, openings 1901 and 1902 are detectors and openings 1903and 1904 are sources.

In FIG. 19, the openings are positioned symmetrically such that a linedrawn through openings 1901 and 1902 is parallel, and equal, to a linethrough openings 1903 and 1904. Additionally, a line drawn throughopenings 1901 and 1903 is parallel, and equal, to a line throughopenings 1902 and 1904.

In an implementation, the distances between openings 1901-1902,1902-1904, 1904-1903, and 1903-1901 are all equal; thus, in thisimplementation openings 1901, 1902, 1903, and 1904 form the vertices ofa square. In other implementations, however, four openings may form thevertices of any quadrilateral, such as a rectangle, a rhombus, atrapezoid, or a parallelogram.

Some of the distances between the centers of particular openings areunequal; for instance, the distance between openings 1901 and 1903 doesnot equal the distance between openings 1901 and 1904.

FIG. 20 shows another variation of the implementation of the sensor unitshown in FIG. 18. Similar to FIGS. 18 and 19, this specificimplementation of a sensor unit includes four openings 2001-2004.

However, in this variation, all four of the openings are arranged in aline closer to a first edge of the sensor. Specifically, in this figure,openings 2001-2004 lie in a row parallel to the first edge so that astraight line may be drawn through each opening. In one implementation,openings 2001 and 2002 are detectors and openings 2003 and 2004 aresources.

In this specific implementation, the distance between openings 2001 and2002 is equal to the distance between openings 2002 and 2003; thisdistance is also equal to that between openings 2003 and 2004.

Additionally, the distance between openings 2001 and 2003 equals thatbetween openings 2002 and 2004. In fact, this distance is twice thedistance between each individual opening. Thus, the distance betweenopenings 2001 and 2003 does not equal that between openings 2001 and2002; the former is twice the distance of the latter.

FIG. 21 shows a variation of the implementation of the sensor unit shownin FIG. 20. This implementation of a sensor unit is similarly arrangedto include four openings 2101-2104. Also, this arrangement of openingsis located closer to a first edge of the sensor. However, in thisfigure, openings 2101, 2102, and 2104 lie in a row parallel to the firstedge so that a straight line may be drawn through the center of eachopening, while opening 2103 lies below that straight line.

In this implementation, opening 2103 lies equally spaced betweenopenings 2102 and 2104; in other implementations, opening 2103 can liecloser to one opening than another. In one implementation, openings 2101and 2102 are detectors and openings 2103 and 2104 are sources.

In this specific implementation, as mentioned above, the distancebetween openings 2102 and 2103 equals that between openings 2103 and2104. Aside from this equality, the distances between the openings areunequal. For example, in this implementation, the distance betweenopenings 2101 and 2103 does not equal the distance between openings 2102and 2104 and the distance between openings 2102 and 2103 does not equalthat between openings 2102 and 2104.

FIG. 22 shows a specific implementation of a sensor unit which isarranged to include two openings 2201 and 2202. Similar to FIGS. 20 and21, this arrangement of openings is located closer to a first edge ofthe sensor. Additionally, openings 2201 and 2202 lie in a row parallelto the first edge so that a straight line may be drawn through eachopening. In one implementation, opening 2201 is a detector and opening2202 is a source.

Although we have shown sensor units with two, four, and six openings inthese figures, other implementations may include different numbers ofsensor openings. For instance, there may be three, five, seven, eight,or more openings.

Further, there may be any combination of detectors and sources and thenumber of detectors need not equal the number of sources. For instance,if there are three openings, there may be one detector and two sourcesor two detectors and one source. As another example, if there are eightopenings, there may be two detectors and six sources, five detectors andthree sources, or four detectors and four sources.

This description of the invention has been presented for the purposes ofillustration and description. It is not intended to be exhaustive or tolimit the invention to the precise form described, and manymodifications and variations are possible in light of the teachingabove. The embodiments were chosen and described in order to bestexplain the principles of the invention and its practical applications.This description will enable others skilled in the art to best utilizeand practice the invention in various embodiments and with variousmodifications as are suited to a particular use. The scope of theinvention is defined by the following claims.

The invention claimed is:
 1. A probe for a medical device comprising: acable interface, the cable interface being adapted to allow the probe tobe coupled to a first radiation emitter and a first photodetector,wherein the first radiation emitter and the first photodetector areexternal to the probe; a sensor unit comprising a first source structureand a first detector structure, the first source structure beingarranged to be coupled to the first radiation emitter via the cableinterface, the first detector structure being arranged to be coupled tothe first photodetector via the cable interface; and a marking mechanismoutput, positioned closer to the first detector structure than the cableinterface.
 2. The device of claim 1 wherein the sensor unit comprises asecond source structure and a second detector structure, the secondsource structure being arranged to be coupled to a second radiationemitter via the cable interface, and the second detector structure beingarranged to be coupled to a second photodetector via the cableinterface, wherein the second radiation emitter and the secondphotodetector are external to the probe.
 3. The device of claim 2wherein a first distance is between the first source structure and thefirst detector structure, a second distance is between the first sourcestructure and the second detector structure, a third distance is betweenthe second source structure and the first detector structure, a fourthdistance is between the second source structure and the second detectorstructure, and the first distance is not equal to the fourth distanceand the second distance is not equal to the third distance.
 4. The probeof claim 1 wherein the marking mechanism output comprises an ink nozzle.5. The probe of claim 1 wherein the marking mechanism output ispositioned within ten millimeters of the first detector structure. 6.The probe of claim 1 wherein the marking mechanism output is coupled tothe sensor unit.
 7. The probe of claim 1 comprising: a handle, whereinthe sensor unit is coupled to the handle; and a light emitting diode,coupled to a handle.
 8. The probe of claim 7 wherein the markingmechanism output is coupled to the handle.
 9. A probe of a medicaldevice comprising: a first retaining mechanism, to couple an oximetersensor to the probe, wherein the oximeter sensor comprises a firstsource structure and a first detector structure; a first markingreservoir; a second retaining mechanism, to couple the first markingreservoir to the probe; and a marking mechanism, coupled to the firstmarking reservoir.
 10. The probe of claim 9 wherein the second retainingmechanism removably couples the first marking reservoir to the probe.11. The probe of claim 9 wherein the second retaining mechanism isinternal to the probe.
 12. The probe of claim 9 wherein the firstmarking reservoir comprises a transparent window.
 13. The probe of claim9 comprises: an elongated handle, wherein the first marking reservoir,the second retaining mechanism, and the marking mechanism are coupled tothe handle.
 14. The probe of claim 9 wherein the oximeter sensorcomprises a second source structure and a second detector structure. 15.The probe of claim 9 comprising: a second marking reservoir; and a thirdretaining mechanism, to couple the second marking reservoir to theprobe, wherein the marking mechanism is coupled to the second markingreservoir.
 16. The probe of claim 15 wherein the first marking reservoircomprises a first ink of a first color, and the second marking reservoircomprises a second ink of a second color, different from the first. 17.The probe of claim 9 wherein the marking mechanism marks a tissuesurface by placing ink on the tissue surface.
 18. A probe of a medicaldevice comprising: a first retaining mechanism, to couple an oximetersensor to the probe, wherein the oximeter sensor comprises a firstsource structure and a first detector structure; a first markingreservoir; a second retaining mechanism, to couple the first markingreservoir to the probe; and a marking mechanism, coupled to the firstmarking reservoir, wherein the first marking reservoir comprises a firstink of a first color and the probe further comprises: a second markingreservoir comprising a second ink of a second color, different from thefirst, wherein the second marking source is coupled to the markingmechanism; and a third retaining mechanism to couple the second markingreservoir to the probe.
 19. The probe of claim 18 wherein the oximetersensor comprises a second source structure and a second detectorstructure.
 20. A probe of a medical device comprising: a first retainingmechanism, to couple an oximeter sensor to the probe; a first markingreservoir; a second retaining mechanism, to couple the first markingreservoir to the probe; and a marking mechanism, coupled to the firstmarking reservoir, wherein the first marking reservoir comprises a firstink of a first color and the probe further comprises: a second markingreservoir comprising a second ink of a second color, different from thefirst, wherein the second marking source is coupled to the markingmechanism and a third retaining mechanism to couple the second markingreservoir to the probe, wherein the oximeter sensor comprises a firstsource structure and a first detector structure and the probe comprises:a first radiation emitter coupled to the first source structure; and afirst photodetector coupled to the first detector structure.
 21. A probeof a medical device comprising: a first retaining mechanism, to couplean oximeter sensor to the probe; a first marking reservoir; a secondretaining mechanism, to couple the first marking reservoir to the probe;a marking mechanism, coupled to the first marking reservoir; and a cableinterface, the cable interface being adapted to allow the probe to becoupled to a first radiation emitter and a first photodetector, whereinthe first radiation emitter and the first photodetector are external tothe probe.
 22. A probe comprising: a first retaining mechanism, tocouple an oximeter sensor to the probe, wherein the oximeter sensorcomprises a first source structure and a first detector structure; afirst marking reservoir; a second retaining mechanism, to couple thefirst marking reservoir to the probe; a marking mechanism, coupled tothe first marking reservoir; a first radiation emitter coupled to thefirst source structure; a first photodetector coupled to the firstdetector structure; and a handle, wherein the oximeter sensor is coupledto the handle via the first retaining mechanism, and the markingmechanism is coupled to the handle via the second retaining mechanism.23. The probe of claim 22 wherein the first and second retainingmechanisms are combined into a single mechanism.
 24. The probe of claim22 wherein the marking mechanism comprises a first marking color outputand a second color output, wherein the first marking color output is adifferent color from the second color output.
 25. A probe of a medicaldevice comprising: a first retaining mechanism, to couple an oximetersensor to the probe; a first marking reservoir; a second retainingmechanism, to couple the first marking reservoir to the probe; and amarking mechanism, coupled to the first marking reservoir, wherein theoximeter sensor comprises a first source structure and a first detectorstructure and the probe comprises: a first radiation emitter coupled tothe first source structure; and a first photodetector coupled to thefirst detector structure.
 26. A probe of a medical device comprising: afirst retaining mechanism, to couple an oximeter sensor to the probe; afirst marking reservoir; a second retaining mechanism, to couple thefirst marking reservoir to the probe; and a marking mechanism, coupledto the first marking reservoir, wherein the first marking reservoircomprises a first ink of a first color and the probe further comprises:a second marking reservoir comprising a second ink of a second color,different from the first, wherein the second marking source is coupledto the marking mechanism; a third retaining mechanism to couple thesecond marking reservoir to the probe; and a cable interface, the cableinterface being adapted to allow the probe to be coupled to a firstradiation emitter and a first photodetector, wherein the first radiationemitter and the first photodetector are external to the probe.